Date of Graduation

Spring 2020


Master of Science in Biology



Committee Chair

Alexander Wait


Engineered nanoparticles (ENPs) have seen a drastic increase in their use over the past decade in various consumer products. ENPs will therefore enter terrestrial ecosystems and soils with increasing frequencies, yet research into the effects of ENPs on living organisms and crops is greatly lacking. Currently, there is only one major study reported on the effects of a single ENP, silver quantum dots, on Sorghum bicolor, the 5th largest crop in the world. I examined the effects of a commonly used metal oxide nanoparticle, titanium dioxide (TiO2), on the growth and development of sorghum grown in petri dishes (n=25) with agar media and Murashige and Skoog (MS) media with concentrations of 5, 10, 20, and 40 µg/ml. I measured seedling germination rates, gas exchange rates using a LI-6400 Portable Photosynthesis System, and biomass after 14 days of growth in a growth chamber. There is a significant decrease of on instantaneous water use efficiency rates due to increasing TiO2 concentrations, but all other gas exchange rates, germination rates, and biomass accumulation were not significant. I also grew sorghum in a greenhouse in potting soil (n = 36 pots) with concentrations of 100, 200, 500, and 1000 mg/kg. I measured sorghum physiology and biomass accumulation at full maturity. There were no measurable effects on physiology or biomass accumulation. While my research indicates no negative effects of this ENP on the growth or development in sorghum, further research will be necessary to identify if TiO2 ENPs are taken up and translocated by the plant, as well as possible intergenerational effects of ENP exposure. Future research may also be conducted into the possible application of TiO2 as an antimicrobial agent for use in pesticides or herbicides if no negative effects are found.


Sorghum bicolor, nanomaterials, nanoparticles, titanium dioxide, physiology

Subject Categories

Agronomy and Crop Sciences | Biology | Plant Biology


© Adam Gregory Shoemaker

Open Access